What you have is decel pop and Turbo200R4 is correct in that the intake and exhaust valve overlap will ignite the unspent gas going down the exhaust pipe as well as a too lean condition with the higher flow silencers at less than 6% throttle. If memory serves the 2012 units also had secondary air injection which exacerbates the burning of fuel in the exhaust. Blanking off the SAI will reduce (not eliminate) the decel pop. When I asked about the TuneECU file you have loaded I was curious about the actual file number (like a 20355 from the custom maps page).